#include "md5.h"

/* Constants for Md5Transform routine. */
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

/* F, G, H and I are basic Md5 functions.
*/
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

/* ROTATE_LEFT rotates x left n bits.
*/
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
Rotation is separate from addition to prevent recomputation.
*/
#define FF(a, b, c, d, x, s, ac) {(a) += F ((b), (c), (d)) + (x) + ac; (a) = ROTATE_LEFT ((a), (s));(a) += (b);}

#define GG(a, b, c, d, x, s, ac) {(a) += G ((b), (c), (d)) + (x) + ac; (a) = ROTATE_LEFT ((a), (s));(a) += (b);}

#define HH(a, b, c, d, x, s, ac) {(a) += H ((b), (c), (d)) + (x) + ac; (a) = ROTATE_LEFT ((a), (s));(a) += (b);}

#define II(a, b, c, d, x, s, ac) {(a) += I ((b), (c), (d)) + (x) + ac; (a) = ROTATE_LEFT ((a), (s));(a) += (b);}

const byte
Md5::PADDING[64] = { 0x80 };
const char
  Md5::HEX[16] =
  { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c',
  'd', 'e', 'f'
};


/* Default construct. */
Md5::Md5 ()
{
  reset ();
}

/* Construct a Md5 object with a input buffer. */
Md5::Md5 (const void *input, size_t length)
{
  reset ();
  update (input, length);
}

/* Construct a Md5 object with a string. */
Md5::Md5 (const QString & str)
{
  reset ();
  update (str);
}

/* Return the message-digest */
const byte *
Md5::digest ()
{
  if (!_finished)
    {
      _finished = true;
      final ();
    }
  return _digest;
}


/* Reset the calculate state */
void
Md5::reset ()
{
  _finished = false;

  /* reset number of bits. */
  _count[0] = _count[1] = 0;

  /* Load magic initialization constants. */
  _state[0] = 0x67452301;
  _state[1] = 0xefcdab89;
  _state[2] = 0x98badcfe;
  _state[3] = 0x10325476;
}

/* Updating the context with a input buffer. */
void
Md5::update (const void *input, size_t length)
{
  update ((const byte *) input, length);
}

/* Updating the context with a string. */
void
Md5::update (const QString & str)
{
  update ((const byte *) str.toAscii ().constData (), str.length ());
}

/* Md5 block update operation. Continues an Md5 message-digest
operation, processing another message block, and updating the
context.
*/
void
Md5::update (const byte * input, size_t length)
{
  ulong i, index, partLen;
  _finished = false;

  /* Compute number of bytes mod 64 */
  index = (ulong) ((_count[0] >> 3) & 0x3f);

  /* update number of bits */
  if ((_count[0] += ((ulong) length << 3)) < ((ulong) length << 3))
    _count[1]++;
  _count[1] += ((ulong) length >> 29);
  partLen = 64 - index;

  /* transform as many times as possible. */
  if (length >= partLen)
    {
      memcpy (&_buffer[index], input, partLen);
      transform (_buffer);
      for (i = partLen; i + 63 < length; i += 64)
	transform (&input[i]);
      index = 0;
    }
  else
    {
      i = 0;
    }

  /* Buffer remaining input */
  memcpy (&_buffer[index], &input[i], length - i);
}


/* Md5 finalization. Ends an Md5 message-_digest operation, writing the
the message _digest and zeroizing the context.
*/
void
Md5::final ()
{
  byte bits[8];
  ulong oldState[4];
  ulong oldCount[2];
  ulong index, padLen;

  /* Save current state and count. */
  memcpy (oldState, _state, 16);
  memcpy (oldCount, _count, 8);

  /* Save number of bits */
  encode (_count, bits, 8);

  /* Pad out to 56 mod 64. */
  index = (ulong) ((_count[0] >> 3) & 0x3f);
  padLen = (index < 56) ? (56 - index) : (120 - index);
  update (PADDING, padLen);

  /* Append length (before padding) */
  update (bits, 8);

  /* Store state in digest */
  encode (_state, _digest, 16);

  /* Restore current state and count. */
  memcpy (_state, oldState, 16);
  memcpy (_count, oldCount, 8);
}

/* Md5 basic transformation. Transforms _state based on block. */
void
Md5::transform (const byte block[64])
{
  ulong a = _state[0], b = _state[1], c = _state[2], d = _state[3], x[16];
  decode (block, x, 64);

  /* Round 1 */
  FF (a, b, c, d, x[0], S11, 0xd76aa478);	/* 1 */
  FF (d, a, b, c, x[1], S12, 0xe8c7b756);	/* 2 */
  FF (c, d, a, b, x[2], S13, 0x242070db);	/* 3 */
  FF (b, c, d, a, x[3], S14, 0xc1bdceee);	/* 4 */
  FF (a, b, c, d, x[4], S11, 0xf57c0faf);	/* 5 */
  FF (d, a, b, c, x[5], S12, 0x4787c62a);	/* 6 */
  FF (c, d, a, b, x[6], S13, 0xa8304613);	/* 7 */
  FF (b, c, d, a, x[7], S14, 0xfd469501);	/* 8 */
  FF (a, b, c, d, x[8], S11, 0x698098d8);	/* 9 */
  FF (d, a, b, c, x[9], S12, 0x8b44f7af);	/* 10 */
  FF (c, d, a, b, x[10], S13, 0xffff5bb1);	/* 11 */
  FF (b, c, d, a, x[11], S14, 0x895cd7be);	/* 12 */
  FF (a, b, c, d, x[12], S11, 0x6b901122);	/* 13 */
  FF (d, a, b, c, x[13], S12, 0xfd987193);	/* 14 */
  FF (c, d, a, b, x[14], S13, 0xa679438e);	/* 15 */
  FF (b, c, d, a, x[15], S14, 0x49b40821);	/* 16 */

  /* Round 2 */
  GG (a, b, c, d, x[1], S21, 0xf61e2562);	/* 17 */
  GG (d, a, b, c, x[6], S22, 0xc040b340);	/* 18 */
  GG (c, d, a, b, x[11], S23, 0x265e5a51);	/* 19 */
  GG (b, c, d, a, x[0], S24, 0xe9b6c7aa);	/* 20 */
  GG (a, b, c, d, x[5], S21, 0xd62f105d);	/* 21 */
  GG (d, a, b, c, x[10], S22, 0x2441453);	/* 22 */
  GG (c, d, a, b, x[15], S23, 0xd8a1e681);	/* 23 */
  GG (b, c, d, a, x[4], S24, 0xe7d3fbc8);	/* 24 */
  GG (a, b, c, d, x[9], S21, 0x21e1cde6);	/* 25 */
  GG (d, a, b, c, x[14], S22, 0xc33707d6);	/* 26 */
  GG (c, d, a, b, x[3], S23, 0xf4d50d87);	/* 27 */
  GG (b, c, d, a, x[8], S24, 0x455a14ed);	/* 28 */
  GG (a, b, c, d, x[13], S21, 0xa9e3e905);	/* 29 */
  GG (d, a, b, c, x[2], S22, 0xfcefa3f8);	/* 30 */
  GG (c, d, a, b, x[7], S23, 0x676f02d9);	/* 31 */
  GG (b, c, d, a, x[12], S24, 0x8d2a4c8a);	/* 32 */

  /* Round 3 */
  HH (a, b, c, d, x[5], S31, 0xfffa3942);	/* 33 */
  HH (d, a, b, c, x[8], S32, 0x8771f681);	/* 34 */
  HH (c, d, a, b, x[11], S33, 0x6d9d6122);	/* 35 */
  HH (b, c, d, a, x[14], S34, 0xfde5380c);	/* 36 */
  HH (a, b, c, d, x[1], S31, 0xa4beea44);	/* 37 */
  HH (d, a, b, c, x[4], S32, 0x4bdecfa9);	/* 38 */
  HH (c, d, a, b, x[7], S33, 0xf6bb4b60);	/* 39 */
  HH (b, c, d, a, x[10], S34, 0xbebfbc70);	/* 40 */
  HH (a, b, c, d, x[13], S31, 0x289b7ec6);	/* 41 */
  HH (d, a, b, c, x[0], S32, 0xeaa127fa);	/* 42 */
  HH (c, d, a, b, x[3], S33, 0xd4ef3085);	/* 43 */
  HH (b, c, d, a, x[6], S34, 0x4881d05);	/* 44 */
  HH (a, b, c, d, x[9], S31, 0xd9d4d039);	/* 45 */
  HH (d, a, b, c, x[12], S32, 0xe6db99e5);	/* 46 */
  HH (c, d, a, b, x[15], S33, 0x1fa27cf8);	/* 47 */
  HH (b, c, d, a, x[2], S34, 0xc4ac5665);	/* 48 */

  /* Round 4 */
  II (a, b, c, d, x[0], S41, 0xf4292244);	/* 49 */
  II (d, a, b, c, x[7], S42, 0x432aff97);	/* 50 */
  II (c, d, a, b, x[14], S43, 0xab9423a7);	/* 51 */
  II (b, c, d, a, x[5], S44, 0xfc93a039);	/* 52 */
  II (a, b, c, d, x[12], S41, 0x655b59c3);	/* 53 */
  II (d, a, b, c, x[3], S42, 0x8f0ccc92);	/* 54 */
  II (c, d, a, b, x[10], S43, 0xffeff47d);	/* 55 */
  II (b, c, d, a, x[1], S44, 0x85845dd1);	/* 56 */
  II (a, b, c, d, x[8], S41, 0x6fa87e4f);	/* 57 */
  II (d, a, b, c, x[15], S42, 0xfe2ce6e0);	/* 58 */
  II (c, d, a, b, x[6], S43, 0xa3014314);	/* 59 */
  II (b, c, d, a, x[13], S44, 0x4e0811a1);	/* 60 */
  II (a, b, c, d, x[4], S41, 0xf7537e82);	/* 61 */
  II (d, a, b, c, x[11], S42, 0xbd3af235);	/* 62 */
  II (c, d, a, b, x[2], S43, 0x2ad7d2bb);	/* 63 */
  II (b, c, d, a, x[9], S44, 0xeb86d391);	/* 64 */
  _state[0] += a;
  _state[1] += b;
  _state[2] += c;
  _state[3] += d;
}

/* Encodes input (ulong) into output (byte). Assumes length is
a multiple of 4.
*/
void
Md5::encode (const ulong * input, byte * output, size_t length)
{
  for (size_t i = 0, j = 0; j < length; i++, j += 4)
    {
      output[j] = (byte) (input[i] & 0xff);
      output[j + 1] = (byte) ((input[i] >> 8) & 0xff);
      output[j + 2] = (byte) ((input[i] >> 16) & 0xff);
      output[j + 3] = (byte) ((input[i] >> 24) & 0xff);
    }
}


/* Decodes input (byte) into output (ulong). Assumes length is
a multiple of 4.
*/
void
Md5::decode (const byte * input, ulong * output, size_t length)
{
  for (size_t i = 0, j = 0; j < length; i++, j += 4)
    {
      output[i] = ((ulong) input[j]) | (((ulong) input[j + 1]) << 8) |
	(((ulong) input[j + 2]) << 16) | (((ulong) input[j + 3]) << 24);
    }
}


/* Convert byte array to hex string. */
QString
Md5::bytesToHexString (const byte * input, size_t length)
{
  QString str;
  for (size_t i = 0; i < length; i++)
    {
      int t = input[i];
      int a = t / 16;
      int b = t % 16;
      str.append (QChar (HEX[a]));
      str.append (QChar (HEX[b]));
    } return str;
}


/* Convert digest to string value */
QString Md5::toString ()
{
  return bytesToHexString (digest (), 16);
}
